1. Field of the Invention
The present invention relates to a solid state imaging device for digital cameras or the like, and more particularly to a solid state imaging device with an improved heat radiation performance.
2. Background Arts
Digital cameras use solid state imaging devices, such as a CCD image sensor, to convert images into digital image data and store it in recording media such as built-in memory and memory cards. The solid state imaging devices, whether the CCD image sensors or CMOS image sensors, generally have a light receiving area with photodiodes arranged thereon in a matrix form, a charge transfer section for transferring signal charges from the light receiving area, and an amplifier that amplifies the signal charges coming from the charge transfer section.
Recent advance in technology promotes the solid state imaging devices to have more pixels while get more downsized, and therefore the solid state imaging devices become to generate more heat. There are the Japanese patent laid-open publication No. 2000-223603 and the U.S. Pat. No. 6,525,409 (corresponding to the Japanese patent laid-open publication No. 2001-68578) that disclose structures for cooling the solid state imaging devices to prevent excessive heat generation thereof. The solid state imaging device, disclosed in the publication No. 2000-223603, is composed of a CCD image sensor chip (semiconductor substrate), a metal land on which the CCD image sensor chip is mounted, and a package that seals the CCD image sensor chip and the metal land. This package is provided with an opening that exposes the metal land, and the heat of the CCD image sensor chip is dissipated from the opening through the metal land. The CCD package disclosed in the U.S. Pat. No. 6,525,409, on the other hand, includes a metal radiation member that makes contact with the CCD image sensor chip (semiconductor substrate). The heat of the CCD image sensor chip is dissipated through this radiation member.
While the above structures are both intended for cooling the entire device, high heat generating components such as the amplifier and the like are not concerned individually. Accordingly, their heat radiation performance is insufficient.